As modern offices, laboratories, work shops, etc. require more and more sophisticated electronic equipment, easy and flexible access to electrical wiring and data and communication cables becomes increasingly important. An object of this invention is to provide a modular interstitial concrete sub-floor which is constructed so that such access is available at all times and anywhere on the floor of the work area, and to achieve this at a price lower than that of existing systems.
The invention comprises a modular interstitial concrete sub-floor which includes a molded floor covering which is mounted on a regular concrete floor to create cavities which serve as cable ducts. The floor covering forms a blind shell or formwork for an upper floor layer of concrete. The blind shell is set in sheets of desired square or rectangular size on the floor at the time of construction of the building or a renovation. It is shaped of rigid hollow pyramidal trunks protruding from a reinforced frame, thus providing an interconnected system of cavities. The side panels of the pyramidal trunks have a prefered angle of 60.degree. to 75.degree..
The interstitial concrete sub-floor of the present invention is supported on a framework which is similar in some respects to the bearing sheet described in Swiss Patent No. CH654 059 A5. However, the blind shell of the sub-floor of the present invention involves the use of simple rigid plastic, aluminum, hard foam, or the like, egg-crate like modules, which are bonded together in a uni-planar relationship to provide the formwork for the concrete, as compared with the flexible bearing sheets disclosed in the Swiss patent which, as described in the patent require reinforcement and are somewhat awkward to use.
The interstitial sub-floor of the invention serves the same general purpose as the flooring described in Wiesman, U.S. Pat. No. 2,259,674, which uses corrugated metal sheets under concrete to provide wiring conduits extending across the floor in one direction only. The sub-floor of the present invention is advantageous, however, it is easy to set up, is economical to produce, and in that it provides a grid of ducts and conduits extending in mutually perpendicular directions under the subfloor. The ducts are accessible at any time for electrical, telephone and other leads and cables. Accordingly, sockets and junction boxes may be mounted in each room as required and at any desired positions. Moreover, cable installations from room-to-room may be easily effectuated, whenever desired.
The interstitial sub-floor of the invention is also advantageous in that it exhibits relatively high compression strength and bending tension, as well as Brinell hardness, as compared with conventional sub-floors. The smooth surface of the interstitial sub floor of the invention is free from expansion joints and raised corners, or other deformations, and it is ideally suited for the laying of the usual floor coverings.
The interstitial sub-floor of the invention is useful not only in the construction of new buildings, but in the renovation of old buildings. The rigid nature of the plastic modular framework included in the sub-floor of the invention facilitates the pouring of the concrete, and the formation of the concrete layer of the sub-floor assembly.